Morphological variation and a remarkable new sexual dimorphism in the Pseudocyclops xiphophorus population of Lake Faro in northeastern Sicily

Authors

  • Cinzia Brugnano Department of Animal Biology and Marine Ecology, Messina University
  • Geoffrey A. Boxshall Department of Zoology, The Natural History Museum. London
  • Giuseppe Costanzo Department of Animal Biology and Marine Ecology, Messina University
  • Giacomo Zagami Department of Animal Biology and Marine Ecology, Messina University

DOI:

https://doi.org/10.3989/scimar.2009.73n2347

Keywords:

Pseudocyclops xiphophorus population, Lake Faro, morphotypes, sexual dimorphism, morphological observation and interbreeding experiments

Abstract


The population of P. xiphophorus in Lake Faro exhibits variation in the form of caudal seta V. In some specimens of both sexes, this seta is spatulate but in others it is slender and unmodified. Occasional specimens are asymmetrical. In addition to this variation in caudal seta form, the Lake Faro population displays variation in male body length and in the extent of the sexually dimorphic specialisation of the right swimming leg 2. The scale of these differences between the morphotypes might suggest their taxonomic treatment as distinct species. The modification of the distal two segments of the exopod of right leg 2 in the male is a unique sexual dimorphism. We infer, from the presence of this hook on the right exopod in adult males only, that it is involved in mating behaviour. Laboratory-based breeding experiments between females and males showing different combinations of these characters were also performed. Experiments comparing egg production rates in females that have mated with modified or unmodified males revealed no significant differences. It appears therefore that gene flow is not interrupted between the morphotypes and that reproductive segregation does not occur. Observations of male leg 5 morphology and musculature revealed no significant differences between the two P. xiphophorus morphotypes.

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References

Boxshall, G.A. – 1982. On the anatomy of the misophrioid copepods, with special reference to Benthomisophria palliata Sars. Phil. Trans. Roy. Soc. Lond. Ser. B., 297: 125-181. doi:10.1098/rstb.1982.0036

Boxshall, G.A. and R. Böttger. – 1987. Two new species of Oncaea (Copepoda: Poecilostomatoida) from the Red Sea and a redescription of O. atlantica Shmeleva. J. Plankton Res., 9(Suppl. 3): 553-564. doi:10.1093/plankt/9.3.553

Brugnano, C., G. Zagami and A. Granata. – 2006. Preliminary data on egg production rates of Pseudocyclops xiphophorus Wells, 1967 from the brackish lake Faro (North-eastern Sicily). Chem. Ecol., 22(Suppl. 1): 191-195. doi:10.1080/02757540600572255

Dawson, J.K. – 1977. A new species of Pseudocyclops (Copepoda: Calanoida) from the southern California coast. Trans. Am. Micros. Soc., 96: 247-253. doi:10.2307/3226100

Elgmork, K. and G. Halvorsen. – 1997. Intraspecific morphological variation in a freshwater copepod (Crustacea) in relation to geographic distribution and environment. Can. J. Zool., 76: 751-762. doi:10.1139/cjz-76-4-751

Esterly, C.O. – 1911. Calanoida Copepoda from the Bermuda Islands. Proc. Am. Acad. Arts Sci., 47: 219-226

Fosshagen, A. – 1968. Marine Biological Investigations in the Bahamas. 4. Pseudocyclopidae (Copepoda, Calanoida) from the Bahamas. Sarsia, 32: 39-62.

Fosshagen, A. – 1970. Marine Biological Investigations in the Bahamas. 15. Ridgewayia (Copepoda, Calanoida) and two new genera of calanoids from the Bahamas. Sarsia, 44: 25-58.

Genovese, S. – 1963. Osservazioni preliminari sullo zooplancton degli stagni salmastri di Ganzirri e di Faro. Boll. Pesca, Pescic., Idrobiol., 1: 1-12.

Giesbrecht, W. – 1892. Systematik und Faunistik der pelagishen Copepoden des Golfes von Neapel und der angrenzenden Meeres-Abschnitte. Fauna und Flora Neapel XIX, pp. 507. Taf. 30, fig. 3, 18, 33; Taf. 43, fig 7, 20-22.

Huys, R. and G.A. Boxshall. – 1991. Copepod evolution. The Ray Society Editors, London, U.K.

Krišnic´, F. and S.J. Malt. – 1985. Little known species of Oncaeidae (Cyclopoida) from the South Adriatic. J. Plankton Res., 7: 189-199. doi:10.1093/plankt/7.2.189

Labbé, A. – 1929. Relations gènètiques de Paracartia grani G. O. Sars et d’Acartia (Acartiura) clausii Giesbrecht. Bull. Biol. France Belgique, 63: 565-619.

Lee, C.E. and B.W. Frost. – 2002. Morphological stasis in the Eurytemora affinis species complex (Copepoda: Temoridae). Hydrobiologia, 480: 111-128. doi:10.1023/A:1021293203512

Nishida, S. – 1985. Taxonomy and distribution of the family Oithonidae (Copepoda; Cyclopoida) in the Pacific and Indian Oceans. Bull. Ocean Res. Inst. Univ. Tokyo, 20: 1-167.

Ohtsuka, S., A. Fosshagen and S. Putchakarn. – 1999. Three new species of demersal calanoid copepod Pseudocyclops from Phuket, Thailand. Plankton Biol. Ecol., 46(Suppl.2): 132-147.

Ohtsuka, S. and R. Huys. – 2001. Sexual dimorphism in calanoid copepods: morphology and function. Hydrobiologia, 453/454: 441-466. doi:10.1023/A:1013162605809

Sars, G.O. – 1904. Description of Paracartia grani, a peculiar Calanoid occurring in some of the Oysterbeds of Western Norway. Bergen Mus. Bergen, 4: 1-14, 3 pl.

Sewell, R.B.S. – 1932. The Copepoda of the Indian Seas. Calanoida. Mem. Indian Mus., 10: 330-333.

Shmeleva, A.A. and E.P. Delalo. – 1965. A new species of the genus Oncaea (Copepoda: Cyclopoida) from the Mediterranean Sea. Zool. Zh., 44: 1562-1565 (in Russian).

Truper, H.G. and S. Genovese. – 1968. Characterization of photosynthetic sulfur bacteria causing red water in Lake Faro (Messina, Sicily). Limnol. Oceanogr., 13(Suppl. 2): 225-232.

Vervoort, W. – 1964. Free-living Copepoda from Ifaluk Atoll in the Caroline Islands with notes on related species. Bull. U.S. Natn. Mus., 236: 1-431.

Wells, J.B.J. – 1967. The littoral Copepoda (Crustacea) from Inhaca Island, Mozambique. Trans. R. Soc. Edinburgh, 67: 189-358.

Zagami, G., G. Costanzo and N. Crescenti. – 2005. First record in Mediterranean Sea and redescription of the bentho-planktonic calanoid copepod species Pseudocyclops xiphophorus Wells, 1967. J. Mar. Systems, 55: 67-76. doi:10.1016/j.jmarsys.2004.07.018

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Published

2009-06-30

How to Cite

1.
Brugnano C, Boxshall GA, Costanzo G, Zagami G. Morphological variation and a remarkable new sexual dimorphism in the Pseudocyclops xiphophorus population of Lake Faro in northeastern Sicily. scimar [Internet]. 2009Jun.30 [cited 2021Sep.17];73(2):347-55. Available from: https://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/1067

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